Composite floor structure

ABSTRACT

A composite floor structure comprises a mortar layer set by a mineral agent and a carrier plate adjoining the lower surface of the mortar layer. The carrier plate has upwardly projecting structural members extending into the mortar. The dimensions of the mortar coating over the structural members are so low that the structures created in the mortar by the structural members represent weak areas. When stresses arise in the mortar layer, joint face assemblies connecting weak areas are formed to reduce stress in a uniform manner. By forming different joint face assemblies, a joint face structure is produced, wherein to reduce stress, the stress causing the mortar to fracture only results in a low level of longitudinal change in each individual joint face. Consequently, each individual joint face only takes the form of a microcrack.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to a composite floor structure comprising a mortarlayer set by a mineral agent and a the carrier plate substantiallyconsisting of a flat basic element and a great number of upwardlyprojecting structural elements extending into the mortar, the elementshaving substantially the same height.

2. The Prior Art

Composite floor structures are adequately known and are employed, forexample as subfloors when floor heating systems are to be installed.Such composite floor structures representing the subfloor for the finalfloor covering are based on the concept of the floating compositionfloor; i.e., the composition floor is separated from the supportingsubfloor by a soft intermediate layer and is not connected with thelatter but only rests on the intermediate layer. The composition flooris provided to serve as a load-distributing layer for uniformlyadmitting forces of load via the intermediate layer into the supportingsubfloor, for example a concrete floor.

The carrier plate, which consists of an insulating material, is placedon the supporting subfloor. The upwardly projecting elements areuniformly distributed over the rectangular or square carrier plate. Theheating tubes are maintained clamped between said elements, so that theydo not change their positions when the paste-like composition floor ispoured on. According to the concept of the floating composition floor,the thickness of the latter has to be dimensioned in such a way that thecomposition floor forms an inherently load-carrying floor plate. Forassuring adequate load-carrying capacity it is recommended for thisreason also in German ATV-DIN 18353 that the mortar covering above theprojecting elements has a thickness of at least 45 mm. However, forfloors subjected to higher loads it is recommended that the minimumthickness of the composition floor be increased. If cement compositionfloors are to be installed, it is necessary, furthermore, to reinforcedsuch composition floors.

Based on the covering proposed by the above standard, the compositionfloors installed in the sector of residential construction work have aminimum overall thickness of 45 mm plus the diameter of the heatingtubes. If such diameter comes to 18 mm, the total thickness of thecomposition floor amounts to 63 mm.

Mortars set with mineral agents, for example the composition floorsaddressed above, set with a certain loss of volume. The different waterrelease properties and temperature influences acting on the top andbottom sides of the mortar layer lead to different changes in lengthwhen the mortar layer sets, with the result that the mortar bulges.

However, bulging of the mortar layer occurs particularly also ifdifferent moisture contents are contained in the installed mortar layer,for example when a higher content of moisture is present in the lower,deeper zone of the mortar layer than in the zone on top, which is closeto the floor covering. This then leads to typical concave/convexdeformation. If the mortar layer is covered with a rigid floor coveringmaterial, this leads to shear-off of the covering or to cracking.

Bulging of the mortar plate is unavoidable especially when floor heatingtubes are installed. In the lower zone of the mortar layer adjoining thecarrier plate, the temperature amounts to, for example about 40° C.because of its direct contact with the heating tubes. However, as only atemperature of about 25° C. is dissipated into the room on top of thefloor covering, a temperature gradient of 15° C. develops within thelayer of mortar. When heating up, the lower regions of the mortar layerwill therefore thermally expand to a distinctly higher degree than theupper zones of the mortar disposed close to the floor covering. Withaverage room sizes of 18 to 20 square meters, bulging caused in thismanner may be in the order of magnitude of up to 15 mm in heightmeasured along the edges of the floor plate, with destruction of themarginal joint terminations in this process.

The effects bulging has on the floor are varied. For example,periodically recurring bulging, which naturally always develops indifferent locations in the mortar, for example in the course of theheating period in the winter and the nonheating period during thesummer, may lead to growing denting of the carrier plate installedunderneath the mortar layer, such plate consisting of insulatingmaterial, whereby such denting is caused by the pressure the plateapplies due to the bulging of the structure of the mortar layer. Due toshifting of such pressure peaks the carrier plate disposed underneaththe mortar is deformed to such an extent that the entire floor plate maysag in the course of some time.

The consequence of bulging of the layer of mortar is that certain areasof the latter lift off from the carrier plate or from its sublayers, sothat even distribution of the forces in the carrier plate or in thesublayer is no longer possible. Under load, this then poses the riskthat the mortar plate fractures for relieving the stress, forming acrack. Even though such fractures may go unnoticed with yielding floorcoverings such as, for example, wall-to-wall carpeting, this will causecracking also of rigid floor coverings installed on the mortar plate,for example such as tiles. Moreover, bulging leads to changes in thelength of the top and bottom sides of the mortar layer. The shearingstress occurring as a result of such changes between the layer of mortarand the floor covering leads to detachment and even fracture of therigid floor covering.

In order to counteract the phenomenon of bulging and the uncontrolledfracturing of the floor caused thereby, a change was made by reducingthe degree of bulging by segmenting the floor areas, The individualmortar plates may then be separated from each other by expansion joints,trowel cuts, or so-called apparent or pseudo joints. Even though overallbulging of the individual mortar plates has been reduced in this manner,bulging still occurs to varying degrees within the individual segments,which may lead to unintended step-like bordering-up of individual floorsegments against each other within the area of the joints. Furthermore,making provision for joints in the course of installation of the mortaris labor-intensive especially when larger floor areas--for example onsales premises or in larger residential rooms--have to be segmented withsuch expansion joints, which, moreover, need to be taken into accountwhen the floor covering is installed later. Furthermore, mortarstructures have to completely set first over at least 28 days accordingto acknowledged rules, so that shrinking is largely completed before arigid floor covering can be applied. Even with composite mortarstructures, whereby the mortar enters into a direct bond with thesubfloor consisting of, for example concrete, the problem to be dealtwith is that if the shrinking property of the subfloor is different fromthe one of the mortar, the layer of the latter becomes detached from thesubfloor and cracking and bulging will then occur in the layer ofmortar.

SUMMARY OF THE INVENTION

Based on the state of the art discussed above the invention, therefore,is based on the problem of creating a composite floor structure which,in spite of the use of a mortar set by a mineral agent, minimizes thephenomenon of bulging at least to such an extent that the risk ofthrough-extending cracking is avoided even in connection with largerfloor areas not segmented by expansion joints, so that constructionswith rigid floor coverings can be produced damage-free as well.

According to the invention, the problem is solved in that the mortarcovering above the projecting structural elements is dimensioned so lowthat the negative structures formed in the mortar by the structuralelements represent predefined weak areas, so that when stresses occur inthe mortar layer, the weak areas are starting points for a substantialuniform stress reduction by the system of separation areas spreadingbetween the negative structures.

The invention makes use of the novel finding that for producing aload-bearing mortar layer it is not necessary to make provision for acovering with a thickness as found in the state of the art. The fact israther that the load bearing capacity of the composition floor onseparation layers under load is governed by adequate and uniformdistribution of the load. The negative structures formed by thestructural elements projecting into the bottom side of the mortar layerrepresent weak areas with respect to the overall thickness of the mortarlayer. When stresses occur within the layer of mortar, be it in thecourse of setting of the mortar or on account of any temperaturegradient existing when a floor heating system is used in the mortar bed,an assembly of joint faces develops in the covering mortar layerstarting from the weak areas for reducing the stresses. By apredetermined arrangement of such weak areas it is possible topredetermine along which lines the assembly of joint faces will develop.Since a great number of projecting structural elements are associatedwith a carrier plate, uniform reduction of the stress is possiblesubstantially across the entire mortar plate, with the consequence thatdue to the great number of joint faces involved, each joint face has tocompensate only a fraction of the total change in length required forreducing the stress. Therefore, each individual joint face has thedimensions of a micro-hairline crack. Therefore, larger,through-extending cracks, which tear up rigid floor coverings, cannotoccur. Likewise, no noticeable bulging occurs, as the triggering forcesin the negative structures are compensated in the negative structures ofthe developing assemblies of joint faces.

Furthermore, due to the low dimensioning of the mortar covering on topof the upwardly projecting structural elements of the carrier plate, themortar covering on top of installed floor heating tubes is distinctlyreduced as well. The lower overall thickness thus conditions also alower temperature gradient and thus superior exploitation andcontrollability of the heat radiated by the floor heating tubes.

The composite floor structure as defined by the invention offersconsiderable advantages over those of the prior art also with respect toits manufacture. The mortar bed sets at a distinctly higher rate due toits lower overall thickness. Application of the final floor covering ispossible after only about 5 days depending on the thickness of thecomposition floor because shrinking of the mortar plates on account ofthe developing assemblies of joint faces is uniformly compensated acrossthe total area.

Owing to the predetermined reduction in the stress of the compositefloor structure, which can distribute itself uniformly across the entirefloor area as well due to the preferably uniform distribution of thestructural elements of the carrier plate, it is no longer necessary thatlarger floor areas have to be segmented by introducing expansion orseparation joints.

With composition floor or mortar layers in a composite, a directadhesive contact has to be produced with the subfloor. This isaccomplished with the help of break-throughs suitably provided in thecarrier plate. As opposed to carrier plates made from yieldinginsulating material, for which provision is made in connection withfloating composition floors, carrier plates for composite floorstructures are generally inflexible and therefore consist of, forexample metal sheet or plastic material. The projecting structuralelements serves for reducing the stress caused by the difference indimensional behavior between the composition floor structure or a mortarlayer and the subfloor. The layer of the composition floor or layer ofmortar otherwise may be designed very thin, as occurring loads aredirectly introduced into the subfloor. Carrier plates withoutbreak-throughs may be joined with the subfloor by gluing, so that theload is directly introduced into the subfloor.

For the sake of better understanding, mortar is understood within theframework of the present disclosure to be any paste-like, settingmixture of water, sand and/or other aggregates produced for setting witha carbonate or sulfate vehicle such as, for example cement or plaster(such as anhydrite, magnesia, cement finish), from which compositioncomposition floors as well as mortar or adhesive mortar layers can beproduced, for example also for gluing tiles.

Provision is made in a preferred exemplified embodiment that thestructural elements of the carrier plate have a circular cross section.Due to such a shape an assembly of joint faces can be formed inidentical ways starting from one structural element in each direction.The direction in which the assembly of joint faces will finally developis therefore exclusively dependent upon in which way the structuralelements are arranged relative to each other.

In a particularly advantageous embodiment of the carrier plate, theindividual structural elements and the mortar layer covering saidelements are characterized by the following ratios:

Height of the structural elements: mortar covering beyond the top edgeof the stuctural elements: smaller than 1:1, in particular less than1:1.5, whereby the maximum mortar covering amounts to 20 mm.

Height of the structural elements: smallest spacing of the structuralelements from each other: smaller than 1:5, in particular less than1:10, whereby the spacing amounts to 200 mm maximum.

The ratios, which define the structural elements, assure that thestructural elements are arranged in such a way that assemblies of jointfaces reducing stress develop in the mortar bed over the shortestdistance between two structural elements, and that the weak areascreated by the structural elements are arranged relative to one anotherin such a way that in the presence of a build-up of stress exceeding acertain degree, the joint face assemblies start to reduce the stress bytearing up the mortar bed in a perforation-like manner.

Provision is made in a useful further development of the invention thatthe upper terminal area of the individual structural elements is arched.This measure supports the development of joint face assemblies startingfrom the areas of the mortar adjoining the roof the structural elements.

In a further development of the useful embodiment, the upward archingsare approximately semispherically shaped, whereby the height of thearching corresponds with the intended covering of the composition floor.Such archings thus serve as an instruction for dimensioning thethickness of the composition floor. Excess flooring finish has to beremoved, for example with a leveling beam resting on at least two ofsuch archings. It seems to be adequate in this connection if provisionis made for only a certain number of structural elements with thearchings. The remaining structural elements may have some otherconfiguration at their top sides.

In yet another embodiment, the carrier plate has break-throughs disposedbetween the structural elements. When poured, the mortar passes throughthe break-throughs and glues the mortar bed with the subfloor presentbeneath the carrier plate. Also a composite floor finish can be producedin this way with the composite floor structure as defined by theinvention.

In yet another exemplified embodiment, provision is made that thestructural elements are oblong elements with a long-stretchedrectangular cross section. The structural elements are usefully aligneddisplaced against each other by 90 degrees in pairs, so that theimagined extension of each structural element is aligned in itslongitudinal expanse with the center of the adjacent structural element,the latter being arranged crosswise relative to the former. With such anarrangement of the structural elements it is possible to induce in themortar bed a structure of joint faces that has exactly two joint faceassemblies.

In yet another preferred embodiment, provision is made that the carrierplate is quadrangular, in particular rectangular or square, and that ithas marginal elements by means of which several of such plates can beconnected with each other for covering a larger floor area, whereby twocircumferential sides of each carrier plate are fitted with the oneconnecting element and the other two circumferential sides are equippedwith the other complementing connecting element. The individual carrierplates can then be produced in handy sizes and be plugged together forcovering larger floor areas. Such a connection is particularly usefulalso to prevent the carrier plates from slipping out of place when apaste-like floor finish is applied.

If the floor covering to be installed on the finished compositionflooring is a rigid floor covering, for example such as tiles or naturalstone, it is deemed recommendable if such floor covering is joined withthe top side of the finish of the first composite floor structure bymeans of an additional composite floor structure as defined by theinvention. The carrier plate then acts as a decoupling layer in order tocompensate changes in length in the floor composition layer disposedunderneath as stress is being built up or reduced, and to thus preventsuch changes from being transmitted into the rigid floor covering. Thecarrier plate has distinctly smaller dimensions as the one intended forproducing the composition flooring.

BRIEF DESCRIPTION OF THE DRAWINGS

Additional advantages and developments of the invention are thecomponents of dependent claims as well as of the following descriptionof exemplified embodiments explained by reference to the attachedfigures, in which:

FIG. 1 shows a cross section through a cutout of a composite floorstructure arranged on a substrate and serving as the subfloor.

FIG. 2 is a bottom view of the mortar bed of the composite floorstructure of FIG. 1.

FIG. 3 shows the composite floor structure of FIG. 1 with a rigid floorcovering applied thereto by means of an additional composite floorstructure.

FIG. 4 is a bottom view of a mortar bed of a composite floor structureaccording to another exemplified embodiment; and

FIG. 5 shows a cross section through two carrier plates joined with eachother, with the structural elements of the carrier plates havingdome-like archings for dimensioning the thickness required for theflooring mortar.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

FIG. 1 shows a composite floor structure 1, which is arranged on aconcrete foundation 3 via an insulating board 2 for damping walkingsound.

Composite floor structure 1 has a carrier plate 4 substantiallycomprising a base plate 5 and a great number of upwardly projectingstructural elements 6. The arrangement comprising carrier plate 4 andplastic tubes 7, which are held clamped in said carrier plate, has beencast in flooring mortar 8 up to a predetermined covering height. Mortar8 has a conventional composition of water and sand with additionalaggregates, the components being mixed with cement as the vehicle.

In the above exemplified embodiment, height "H" of structural elements 6amounts to 30 mm. Diameter "D" of structural elements 6 amounts to 60mm, which results in a ratio of H:D of 1:2. The shortest spacing "A"between two structural elements 6 as shown in FIG. 2 comes to 45 mm,which results in a ratio of H:A of 1:1.5. Covering "U" of mortar layer 8above a structural element 6 amounts to 10 mm, resulting in a ratio ofH:U of 1:0.33. The total thickness accordingly amounts to H+U, which inthe exemplified embodiment shown corresponds with 40 mm.

For the purpose of enhancing the engagement between flooring mortar 8and structural elements 6, the latter are designed slightly undercutwhen carrier plate 4 is viewed from the top. Structural elements 4 shownhere taper in the form of a cone toward base plate 5.

When stress builds up in mortar 8, for example due to the development ofa temperature gradient, for example when the floor heating system is putinto operation, mortar 8 is capable of absorbing such stress withoutfracturing up to a certain low degree of deformation. However, if suchdefined limit of stress absorption is exceeded, the negative structuresformed by structural elements 6 in mortar 8 as weak areas act as zonesfor fracture zones for the reduction of stress. Due to the regulararrangement of structural elements 6 on base plate 5, joint faceassemblies are then formed for reducing the stress, such joint faceassemblies preferably developing along the shortest spacing "A" betweentwo structural elements 6. The individual weak points formed bystructural elements 6 are then connected with each other by the jointfaces. The stress is thus reduced in a perforation-like pattern along agreat number of joint faces arranged. in parallel. Each individual jointface consequently compensates only a fraction of the overall stress, sothat each joint face represents itself only as a hairline fissure.

The development of such joint faces connecting the weak areas formed bystructural elements 6 is promoted by making provision for bridges 9connecting structural elements 6 with one another, such bridges beingarranged along the line where joint faces are intended to develop onbase plate 5.

Two of such joint face assemblies 10, 11 are shown in FIG. 2, wheremortar 8 is shown in a bottom view without carrier plate 4. It isclearly visible that the two joint face assemblies 10, 11 develop alongthe shortest spacings "A" between two weak areas formed by structuralelements 6 within the zone of the tracks predetermined by bridges 9.

The excellent properties of composite floor structure 1 have beenverified in a series of tests as well.

In the tests, the composite floor structure as defined by the inventionwas found to be stressable, for example with a multiple of the loadbearing capacity of 1.5 kN/m² specified by applicable regulations fornormal traffic loads in apartment construction in spite of an overalllower thickness of the flooring mortar. As opposed to known compositefloor structures, the composite floor structure as defined by theinvention, however, showed substantially superior results with respectto its bulging property. In particular., cracking that would destroy thefloor covering is prevented.

In other embodiments, provision is made that the structural elementshave a crack formation-favoring polygonal or star-shaped cross sectionalshape. Such structural elements are preferably arranged in such a waythat the shortest spacing between two structural elements extendsbetween two edges of the structural elements. This edges have afavorable effect with respect to direction-induced cracking.

FIG. 3 shows a composite floor structure 1 covered by tiles 12. Tilecovering 12 is glued to the surface of mortar 8 by means of a compositefloor structure 13 of the same type. Carrier plate 14 employed for thispurpose is designed in the same way as carrier plate 4 with respect toits structural elements 15, whereby, however, the absolute dimensioningis distinctly lower. Carrier plate 14 is a deep-drawn plastic foil. Theheight of a structural element 15 as shown in the exemplified embodimentaccording to FIG. 3 amounts to only about 4 mm measured above base plate16. Carrier plate 14 is joined by gluing its underside to the top sideof mortar 8 with mortar 17, whereby carrier plate 14 has break-throughs18 for the passage of mortar 17. Carrier plate 14 serves as a decouplinglayer, so that possible deformations s of composite floor structure 1,in particular of its mortar 8 are not transmitted into tile covering 12.The layer of tile covering adheres with its full surface to the layerconsisting of adhesive mortar and in this way is forming theforce-dominating component, so that changes in length and cracks are nottransmitted to the covering layer. As explained above, movements ofmortar 8 for reducing stress take place only in the order of magnitudeof hairline fissures, so that such movements can be readily absorbed bycarrier plate 14. In the presence of greater movements, mortar layer 17fractures because of the development of joint face assembliescorresponding with the mortar layer 8 described above; however, therigid layer of covering remains undamaged.

In another embodiment not shown, provision is made that a carrier platecorresponding with carrier plate 14 has apertures in the cylindricalsegments of its structural elements. Apertures are provided in this wayin addition to or instead of break-throughs 18, so that a honeycomb-likestructure is obtained, through which the mortar can penetrate the zonelocated beneath the carrier plate.

FIG. 4 shows a bottom view of a flooring mortar 18 in anotherexemplified embodiment. As opposed to the exemplified embodiment shownin FIGS. 1 to 3, the potential fracture zones introduced as weak areas20, 21 by suitable structural elements not shown in FIG. 4 are notpoint-like but arranged in a line. Two joint face assemblies can beformed with such a design, with their longitudinal expanse conforming tothe longitudinal expanse of weak areas 20, 21. The design of such amortar flooring 19 is useful if a metal sheet is used for producing acomposite floor structure instead of carrier plate 4 made frominsulating material. Punched and upwardly bent structural elements areassociated with the metal sheet for producing structures 20, 21.Break-through are produced in this way between the structural elements,through which mortar 19 can pass for gluing it to the subfloor.

In the exemplified embodiment shown in FIG. 5, two different structuralelements 23, 24 are associated with carrier plates 22 shown here only bycutouts. Structural elements 23, 24 have a semispherical bulging 25 ontheir top sides. The height of arching 25 is dimensioned in such a waythat such arching corresponds with the thickness intended for themortar, so that such thickness can be used as an instruction for thedimensioning of the thickness of the mortar. A leveling beam resting onone or several of such archings 25 can then be pulled across the pouredmortar in order to removed any excess amount of the latter. It isassured in this way, on the one hand, that the mortar covering on top ofcarrier plates 22 has an even thickness and that, on the other hand, anoptimal mortar covering is obtained on top of structural elements 23,24.

Furthermore, structural elements 23, 24 have clamping lips 26 arrangedacross the circumference, such clamping lips fixing plastic tubes 7 fora floor heating system in their desired positions between structuralelements 23, 24.

In yet another embodiment not shown, provision is made that drainageducts are installed in the carrier plates on the bottom sides. Thedrainage ducts usefully are duct assemblies intersecting each other.Such drainage ducts are connected with the top sides of the carrierplates by break-throughs, which are dimensioned in such a way thatclogging of the ducts by plaster or mortar is prevented. It is thenpossible with the help of such a carrier plate to produce a compositefloor structure as defined by the invention which is arranged with itsbottom side on a sealing layer, for example a layer of bitumen, andwhich is thus drained. When the carrier plate is placed on the sealinglayer the drainage ducts remain unfilled and thus serve as channels fordraining off seepage water.

    ______________________________________                                        List of Reference Numerals                                                    ______________________________________                                                1  Composite floor structure                                                  2  Insulating board                                                           3  Concrete foundation                                                        4  Carrier plate                                                              5  Base plate                                                                 6  Structural element                                                         7  Plastic tube                                                               8  Mortar                                                                     9  Bridge                                                                    10  Joint face assembly                                                       11  Joint face assembly                                                       12  Tiles                                                                     13  Composite floor structure                                                 14  Carrier plate                                                             15  Structural element                                                        16  Base plate                                                                17  Mortar                                                                    18  Break-through                                                             19  Mortar                                                                    20  Weak area                                                                 21  Weak area                                                                 22  Carrier plate                                                             23  Structural element                                                        24  Structural element                                                        25  Arching                                                                   26  Clamping lip                                                              H   Height of a structural element                                            D   Diameter of a structural element                                          U   Mortar covering within the zone                                               of a structural element                                            ______________________________________                                    

What is claimed is:
 1. A composite floor covering structure with amortar layer (8, 17, 19) set by a mineral agent and a carrier plate (4,14, 22) adjoining the lower surface of the mortar layer (8, 17, 19),said carrier plate substantially consisting of a flat base element (5,16) and upwardly projecting structural elements (6, 15, 23, 24)projecting into the mortar (8, 17, 19) and substantially having the sameheight, whereby the mortar covering (U) above the projecting structuralelements (6, 15, 23, 24) is dimensioned in such a way that the negativestructures formed by the structural elements (6, 15, 23, 24) in themortar (8, 17, 19) represent predefined fracture zones (20, 21) forreducing occurring stresses, characterized in that the structuralelements (6, 15, 23, 24) are spaced from each other and arrangedaccording to a regular pattern with respect to the base element (5, 16)and molded on said element, said structural elements (6, 15, 23, 24)forming in the mortar layer (8, 17, 19) negative structures acting likea perforation, so that when stresses develop in the mortar layer (8, 17,19), the negative structures are starting points for joint faceassemblies (10, 11, 20, 21) spreading between said negative structures.2. The composite structure according to claim 1, characterized by thefollowing ratios for the arrangement of the structural elements (6, 15,23, 24):Height (H) of the structural elements (6, 15, 23, 24) to mortarcovering (U) above the top edge of the structural elements (6, 15, 23,24): lower than 1:1, particularly lower than 1:1.5, whereby the maximummortar covering amounts to 20 mm Height (H) of the structural elements(6, 15, 23, 24) to the smallest spacing (A) of the structural elements(6, 15, 23, 24) from each other: lower than 1:5, preferably lower than1:10, whereby said spacing amounts to 200 mm at the most.
 3. Thecomposite structure according to claim 1, characterized in that theupper terminal surface of the structural elements (24) is arched.
 4. Thecomposite structure according to claim 1, characterized in that thestructural elements are oblong elements with a long-stretchedrectangular cross section.
 5. The composite structure according to claim4, wherein the structural elements are arranged in adjacent pairs offirst and second structural elements 90° to each other, said firststructural element having an imaginary extension along its longitudinalexpanse intersecting the center of the second structural element.
 6. Thecomposite structure according to claim 1, characterized in that the baseelement (5, 16) of the carrier plate (4, 14) has break-throughs (18). 7.The composite structure according to claim 1, characterized in that thecarrier plate (4) consists of an insulating material.
 8. The compositestructure according to claim 1, characterized in that the carrier plateis made from a metal sheet, whereby the structural elements areoutwardly bent segments of the metal sheet.
 9. The composite structureaccording to claim 1, wherein the carrier plate is a plastic foil formedby a punching die in a deep-drawing process.
 10. The composite structureaccording to claim 9, characterized in that the structural elements (15)of the punched plastic foil (14) have apertures for the passage ofmortar.
 11. The composite structure according to claim 1, characterizedin that the carrier plate (4, 14) is quadrangular, in particular square,and has marginal elements by means of which a plurality of such platesare connectable with each other for covering a larger floor area,whereby two circumferential sides of each carrier plate (4, 14, 23, 24)are fitted with the one connecting element and the two othercircumferential sides are equipped with the other connecting elementdesigned as a complementary component.
 12. The composite structureaccording to claim 1, characterized in that an additional compositefloor structure (13) is bonded to the top side of the mortar layer (8)for applying thereto a rigid floor covering (12), whereby provision forthe rigid floor covering (12) is made on the top side of the mortarlayer (17) arranged on the carrier plate (14).
 13. The compositestructure according to claim 1, characterized in that a defined numberof structural elements (24) have an upwardly projecting element (25) ontheir top sides, the height of said element corresponding with thethickness of the provided-for flooring plaster covering.
 14. Thecomposite structure according to claim 13, characterized in that theelement has a semispherical arching (25).
 15. The composite structureaccording to claim 1, characterized in that the structural elements (6,15) of the carrier plate (4, 14) have a circular cross section insectional planes arranged parallel with the areal expanse of the baseelement (5, 16).
 16. The composite structure according to claim claim 1,characterized in that the structural elements of the carrier plate (22)have a polygonal or star-shaped cross section in sectional planesarranged parallel with the areal expanse of the base element (5, 16).